JP4144539B2 - Dynamic damper - Google Patents

Description

  The present invention relates to a dynamic damper that is mounted in a mating pipe member such as a vehicle drive shaft, a propeller shaft, and a tube in a seat, and attenuates vibration generated on the mating pipe member side.

Conventionally, as this type of dynamic damper, for example, as shown in Patent Document 1, it has a plate-shaped radial portion and a cylindrical portion that extends in the axial direction from the outer periphery thereof and is press-fitted into the inner peripheral surface of the propeller shaft. 2. Description of the Related Art A fixed plate, a mass body opposed to a radial direction portion, and a rubber elastic body that connects the radial direction portion and the mass body are known. According to this dynamic damper, since the rubber elastic body undergoes shear deformation with respect to radial input vibration, the radial spring constant can be set low. As a result, the resonance frequency of the dynamic damper is reduced to a low frequency. Therefore, the low-frequency vibration of the propeller shaft can be effectively damped.
JP 2003-262252 A

  By the way, with respect to the dynamic damper, it is necessary to increase the mass of the mass body in order to increase its vibration damping force, but as a result, the shape of the mass body becomes longer in the axial direction and the center of gravity moves away from the radial portion. It becomes. As described above, when the center of gravity of the mass body is separated from the radial portion and the weight thereof is increased, the mass body cantilevered and supported by the radial portion via the rubber elastic body is subjected to radial vibration and swings in the vibration direction. It becomes easy to produce a swing. As a result, the mass body may interfere with the propeller shaft, and the vibration damping function of the dynamic damper is impaired. On the other hand, in order to suppress the swing of the mass body, there is a method of hardening the rubber elastic body, but this suppresses the shear deformation of the rubber elastic body and increases the resonance frequency of the dynamic damper. . That is, with the dynamic damper, it is difficult to sufficiently suppress low-frequency vibration while increasing vibration damping force.

  The present invention is intended to solve the above-described problems, and provides a dynamic damper that is attached in a mating pipe member and can effectively suppress vibration in the radial direction of the mating pipe member, in particular, low-frequency vibration. Objective.

In order to achieve the above object, a structural feature of the present invention is a mounting bracket made of a steel plate that is inserted into a mating pipe member by press fitting and fixed in a state perpendicular to the axial direction of the mating pipe member. The spring constant is reduced so that a pair of mass brackets spaced apart from both sides of the mounting bracket and a shear deformation that elastically connects the pair of mass brackets and both surfaces of the mounting bracket can be performed. Bei example a pair of rubber elastic body has, in the resonance frequency have been engaged in the low frequency corresponding to the bending vibrations of the mating pipe member, and interference between the mating pipe member of mass metal is prevented.

  In the invention configured as described above, rubber elastic bodies are respectively provided on both surfaces of a plate-like mounting bracket that is press-fitted into the mating pipe member and fixed in a state perpendicular to the axial direction of the mating pipe member. Since the pair of mass fittings are attached via the, even if the weight of each mass fitting is reduced, the weight of both mass fittings as a whole can be increased. As described above, since the weight of the entire mass metal is increased, the vibration damping force of the dynamic damper is increased and the weight of each mass metal is not increased, so that the spring constant of the rubber elastic body can be sheared and deformed. The resonance frequency of the dynamic damper can be lowered. Furthermore, since each mass bracket is made lighter and smaller, its center of gravity can be moved closer to the mounting bracket side. Therefore, even if the spring constant of the rubber elastic body is reduced, both mass brackets are resistant to radial vibration. The swinging of the is reliably suppressed.

  Moreover, in this invention, a mounting bracket can be made into disk shape. Thereby, since there is no directionality of the attachment of the mounting bracket to the mating pipe member, the workability of the fitting of the dynamic damper into the mating pipe member is improved. Further, since the mounting bracket is tightly pressed into the inner peripheral surface of the mating pipe member, it is firmly fixed to the mating pipe member.

  Moreover, in this invention, the flange part extended in the axial direction can be provided in the outer periphery with which an attachment metal fitting contacts the internal peripheral surface of a mating pipe member. As described above, since the flange portion extending in the axial direction is provided on the outer peripheral edge of the mounting bracket, the mounting bracket can be smoothly inserted into the mating pipe member in the axial direction. Enhanced. In addition, since the contact area of the mounting bracket with the mating pipe member is increased by the flange portion, the contact strength with the mating pipe member is increased, and the mounting bracket is securely attached to the mating pipe member.

  In the present invention, the surface of the mounting bracket can be covered with a thin rubber coating layer. Thereby, the press-fitting of the mounting bracket to the mating pipe member is smoothly performed through the thin rubber coating layer. Moreover, since the mounting bracket is protected by the rubber coating layer, there is no need to perform rust prevention treatment.

  According to the present invention, a pair of mass metal fittings are attached via rubber elastic bodies to both surfaces of a plate-like mounting metal fitting that is press-fitted into the mating pipe member, so that the weight of each mass metal fitting As a whole, the weight of the mass metal fitting can be increased, thereby reducing the spring constant of the rubber elastic body and lowering the resonance frequency of the dynamic damper, and further suppressing the swing of the mass metal fitting. be able to. As a result, in the present invention, it is possible to reliably prevent interference with the mating pipe member of the mass metal fitting, while ensuring the vibration damping force of the dynamic damper and lowering the resonance frequency thereof, the mating pipe member The low frequency vibration can be effectively suppressed.

Embodiments of the present invention will be described below with reference to the drawings.
1 and 2 are cross-sectional views taken along the line I-I of a dynamic damper fixed in a drive shaft (a mating pipe member) of an automobile, which is a cylindrical rotating shaft having a hollow portion according to the first embodiment. It is shown by the left side view. The dynamic damper 10 is inserted into the drive shaft 1 by press-fitting and is fixed to a plate-shaped mounting bracket 11 that is fixed to the drive shaft 1 in the axial direction perpendicular to the drive shaft 1 and separated from both surfaces of the mounting bracket 11. In addition, a pair of mass fittings 14 arranged coaxially and a pair of rubber elastic bodies 16 that elastically connect the both sides of each mass fitting 14 and the mounting fitting 11 are provided. In the present embodiment, the drive shaft 1 mainly has a large diameter of about 40 to 50 mmφ, and so on.

  The mounting bracket 11 is a substantially rectangular steel plate, both end edges in the longitudinal direction are arc-shaped to match the inner peripheral surface of the drive shaft 1, and are further bent at right angles from both end edges to slightly in the same direction. It has a pair of protruding flange portions 12. The outer diameter of the mounting bracket 11 in the longitudinal direction is slightly larger than the inner diameter of the drive shaft 1 in order to press fit into the drive shaft 1. The mass metal fitting 14 is a cylindrical metal fitting whose outer diameter is about half the inner diameter of the drive shaft 1, and its axial length is also shortened. Moreover, although the mass metal fitting 14 is made small in weight, it is made for the whole weight to become large by combining a pair. The pair of rubber elastic bodies 16 has a cylindrical shape whose outer diameter is about half of the width of the mounting bracket 11 and whose axial length is substantially the same as the axial length of the mass bracket 14. Are formed by vulcanization molding between both surfaces of the mounting bracket 11. The dynamic damper 10 is fixed in a state perpendicular to the drive shaft 1 in the axial direction by being press-fitted into the drive shaft 1 by both flange portions 12 of the mounting bracket 11.

  In the first embodiment configured as described above, a pair of dynamic dampers 10 are provided on both surfaces of a plate-like mounting bracket 11 that is perpendicular to the drive shaft 1 in the axial direction via rubber elastic bodies 16. The mass brackets 14 are attached, and the weight of each mass bracket 14 is relatively light, but the weight of both the mass brackets 14 as a whole is increased. Further, since each mass metal fitting 14 is lightweight, the spring constant of both rubber elastic bodies 16 can be reduced so that shear deformation is possible, so that the resonance frequency of the dynamic damper 10 is changed to the bending vibration of the drive shaft 1. The frequency can be adjusted to a corresponding low frequency of about 90 to 100 Hz. Further, since each mass metal fitting 14 is made lighter and smaller, its center of gravity can be brought closer to the mounting metal fitting 11 side, so even if the rubber elastic body 16 has a small spring constant, The swing of the mass metal fitting 14 is reliably suppressed.

  As a result, in the first embodiment, it is possible to reliably prevent the mass metal member 14 from interfering with the drive shaft 1 and to secure the vibration damping force of the dynamic damper 10 while lowering the resonance frequency thereof. Low frequency vibration of the drive shaft 1 can be effectively suppressed. Moreover, in Example 1, since the flange part 12 extended in the axial direction was provided on both outer peripheral edges of the mounting bracket 11, the press-fitting of the mounting bracket 11 to the drive shaft 1 is smoothly performed in the axial direction. The workability of press fitting is improved. Further, the contact strength between the mounting bracket 11 and the drive shaft 1 is increased by the flange portion 12, so that the contact strength with the drive shaft 1 is increased and the mounting bracket 11 is firmly attached to the drive shaft 1.

  As a modification of the first embodiment, as shown in FIG. 3, the entire surface of the mounting bracket 11 including the flange portion 12 can be covered with a thin rubber coating layer 17. Thereby, the press fitting of the mounting bracket 11 to the drive shaft 1 is smoothly performed through the thin rubber coating layer 17, and the labor of the press fitting work of the mounting bracket 11 is reduced. The mounting strength of the mounting bracket 11 to the drive shaft 1 is also ensured by the rubber coating layer 17. Further, since the mounting bracket 11 is protected by the rubber coating layer 17, it is not necessary to perform a rust prevention process on the mounting bracket 11.

Next, Example 2 will be described.
FIGS. 4 and 5 show a dynamic damper 20 inserted into the drive shaft 1 of the automobile according to the second embodiment in a sectional view and a left side view in the IV-IV line direction. The dynamic damper 20 is the same as the dynamic damper 10 described above, wherein the mounting bracket 21 is a disk, and an annular flange portion 22 slightly extending in the axial direction is provided over the entire circumference. Further, the mass metal fitting 24 is formed into an elongated round bar shape extending in the axial direction, and both the mounting metal fitting 21 and the end face of the mass metal fitting 24 are connected by the rubber elastic body 26, and the entire outer periphery of the mass metal fitting 24 is connected from the rubber elastic body 26. It is covered with an extended thin rubber covering portion 27.

  Also in the second embodiment configured as described above, the resonance frequency of the dynamic damper 20 is set to a low frequency as in the first embodiment. Therefore, the low-frequency vibration of the drive shaft 1 can be attenuated by the dynamic damper 20. . Further, although the mass bracket 24 is long in the axial direction but has a very small diameter, it tends to oscillate in the radial direction as compared with the mass bracket 14 of the first embodiment. Contact is definitely avoided. Therefore, the vibration damping performance of the dynamic damper 20 is not impaired by the swing of the mass metal fitting 24. Furthermore, since the mounting bracket 21 is disc-shaped, there is no direction of insertion of the mounting bracket 21 into the drive shaft 1, so that the workability of insertion of the dynamic damper 10 into the drive shaft 1 is improved. . Further, since the mounting bracket 21 is pressed into the inner peripheral surface of the drive shaft 1 tightly, it is firmly fixed to the drive shaft 1.

  As a modification of the second embodiment, as shown in FIG. 6, the entire surface of the mounting bracket 21 including the flange portion 22 can be covered with a thin rubber coating layer 28 as in the modification of the first embodiment. . Thereby, the press fitting of the mounting bracket 21 to the drive shaft 1 is smoothly performed through the thin rubber coating layer 28. Further, since the mounting bracket 21 is protected by the rubber coating layer 28, it is not necessary to perform the rust prevention treatment.

  In addition, also in the said Example 1 and a modification, a mounting bracket can be made into a disk similarly to Example 2. FIG. Moreover, in each said Example and modification, although the flange part is provided in the outer periphery of the attachment metal fitting, this can also be omitted as needed. Further, in each of the above embodiments and modifications, the dynamic damper is used by being inserted into the drive shaft, but in addition, a cylindrical rotary shaft having a similar hollow portion such as a propeller shaft or the like in the seat And can be used to attenuate the radial vibration. In addition, the dynamic dampers shown in the above embodiments and modifications are merely examples, and can be implemented in various forms without departing from the spirit of the present invention.

  According to the present invention, since the pair of mass metal fittings are attached to both surfaces of the attachment metal fittings that are press-fitted into the mating pipe member through the rubber elastic bodies, respectively, the weight of the mass metal fitting is increased as a whole. It is possible to reduce the spring constant of the rubber elastic body and lower the resonance frequency of the dynamic damper. Therefore, the present invention is useful because it is possible to reliably prevent the mass metal fitting from interfering with the drive shaft and to effectively suppress the low-frequency vibration of the drive shaft 1 while ensuring the vibration damping force of the dynamic damper. It is.

It is sectional drawing of the II line direction of FIG. 2 which shows the dynamic damper inserted by the drive shaft of the motor vehicle which is Example 1 of this invention. It is a left view which shows the dynamic damper. FIG. 6 is a cross-sectional view at an axial position showing a dynamic damper which is a modified example of Embodiment 1. FIG. 6 is a cross-sectional view taken along the line IV-IV in FIG. It is a left view which shows the dynamic damper. It is sectional drawing in the axial position which shows the dynamic damper which is a modification of Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Dynamic damper, 11 ... Mounting bracket, 12 ... Flange part, 14 ... Mass metal fitting, 16 ... Rubber elastic body, 17 ... Rubber coating layer, 20 ... Dynamic damper, 21 ... Mounting bracket, 22 ... Flange part, 24 ... Mass Metal fitting, 26 ... rubber elastic body, 28 ... rubber coating layer.

Claims (4)

A fitting made of a steel plate that is inserted into the mating pipe member by press fitting and fixed in a state perpendicular to the axial direction of the mating pipe member;
A pair of mass brackets spaced from each other on both sides of the mounting bracket;
E Bei a pair of rubber elastic bodies shear deformation spring constant as possible are reduced to respective elastically connecting between both surfaces of the mounting bracket and the pair of mass metal, the resonance frequency of the corresponding pipe member A dynamic damper that is adjusted to a low frequency corresponding to bending vibration and that prevents interference of the mass metal fitting with the mating pipe member . The dynamic damper according to claim 1, wherein the mounting bracket has a disk shape. 3. The dynamic damper according to claim 1, wherein the mounting bracket is provided with a flange portion extending in an axial direction on an outer peripheral edge in contact with an inner peripheral surface of the mating pipe member. The dynamic damper according to any one of claims 1 to 3, wherein a surface of the mounting bracket is covered with a thin rubber coating layer.

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